


The Toy Experiment

by My_Hearts_Song



Series: Experiments [1]
Category: CSI: Crime Scene Investigation
Genre: Age Difference, Anal Plug, Consensual Kink, Domestic, Established Relationship, M/M, Plot What Plot, Porn, Sex Toys, Sexual Experimentation, Workplace Relationship, Workplace Sex
Language: English
Status: Completed
Published: 2012-04-03
Updated: 2012-04-03
Packaged: 2017-11-02 23:23:09
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 1
Words: 2,303
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/374518
Author URL: https://archiveofourown.org/users/My_Hearts_Song/pseuds/My_Hearts_Song
Summary: <blockquote class="userstuff">
              <p>In which Grissom wonders how long it will take until Greg gets uncomfortable with a toy in his ass</p>
            </blockquote>





	The Toy Experiment

It started innocently enough; well, innocent for them. Grissom had just fucked Greg until the younger man screamed (Grissom’s ability to hold off his own orgasm was astounding, really) and then, because Grissom had grown bored of simply lying together, he had shoved a vibrator into Greg and watched his response. Observing was one of his favourite things to do, after all.

After Greg had finished, his cum warm and sticky on his stomach, Grissom had turned off the vibrator, but left it inside. They kissed, with Greg lazy and distracted by the endorphins racing through his body. 

“Mmm, ‘m tired,” Greg murmured sleepily, cuddling into Grissom’s chest. 

“Didn’t you sleep before you came here?” Grissom asked absently. He was sorting through the tasks he would need to do at the lab tonight, some administrative paperwork he had been avoiding. 

“Yeah,” Greg said with a sleep laugh. “You must wear me out.”

Grissom grinned and pulled the slight man closer to him. Greg began dozing, waiving in and out of consciousness. Grissom was still considering this and that, creating a schedule for the night.

Then it occurred to him he hadn’t taken the vibrator out of his lover yet. Curious, he shook Greg until his eyes slide open fully. Greg hummed softly in inquiry.

“You’re still full. Is it bothering you?” Grissom asked, what Greg lovingly called his “scientist voice” appearing.

“No,” Greg mumbled, shifting so he could feel the vibrator more. “I kinda like it just being there.”

“Hmm...how long do you suppose you could keep it inside of you without it getting uncomfortable?” 

And that was the winning question. Greg didn’t know. They had both made estimates and then Grissom had quietly inquired if Greg was willing to test their hypothesis. Grinning, Greg agreed.

So, they had cuddled together on the bed for a while, talking about this and that. Then Grissom had gotten hungry. Greg confessed the vibrator was too bulky to move around with, so they had switched to a slimmer dildo, the one with the swirls Greg liked so much. They had eaten dinner, then Greg watched a movie while Grissom read one of those scientific journals he always had his nose into. Two hours had passed by the time Grissom asked how Greg was feeling with the dildo. Greg was still quite fond of having the toy inside of his ass, so they carried on. They both showered, separately because Greg had a thing about his hair, and before they knew it, it was time to go to work.

Now, they had a dilemma. 

“Is it professional?” Grissom had asked uncertainly.

Greg laughed. “Well, it’s not as if I’m going to walk up to the superintendant and tell him!” 

“You have a point.”

“We’ll need to change the toy though. This one is fine when I’m sitting around not doing much, but I’ll need something more...durable for work.” He grinned impishly.

Grissom nodded and herded Greg towards the bedroom with a hand on the small of his back. Greg undressed and sat on the bed patiently while Grissom inspected the toychest for something suitable. He decided on a slim butt plug and held it up for approval.

Greg considered it a moment. “I want something bigger.”

Grissom smirked at him, one eyebrow lifting. “My kinky little slut,” he said fondly, dropping it to find a bigger butt plug. The words went straight to Greg’s dick. It wasn’t often the dignified man used such naughty words and every single time, Greg got off on it. 

He settled on one Greg had bought to add to his collection, bright red and more ostentatious than anything he would have chosen. He must admit though, seeing the flash of colour in Greg’s hole is very nice. 

Grissom wandered closer to the bed and manipulated Greg’s body until he was on his hands and knees, face down and ass in the air. Such a blatant pose of submission made Grissom’s erection appear and he fucked Greg before plugging him.

As Greg left the apartment, Grissom’s cum was still warm beneath the plug.

_________________________________________________________________

Grissom went to the lab every hour, questioning Greg about this piece of evidence or that, but Greg knew their little experiment was the true reason Grissom kept appearing.

When Grissom gave him a raised eyebrow in question, he would smirk or grin or lick his lips. 

It was about midnight when Grissom showed again, while Greg was busy at the machine. Sensing his lover behind him, Greg had placed his hands on the table and arched his back, displaying his ass for Grissom to admire. The way Grissom cleared his throat was his reward.

“Did you match the hair yet?” Grissom asked. To everyone else, he sounded completely normal, maybe a little bit irritated. But when Greg turned around to smile at him, he noticed the little things that told him Grissom wanted to fuck him, like the way his pupils were dilated or the hint of a blush on his neck. 

“Yes, I did,” Greg said, moving to sit back down on his stool. He noticed the way Grissom’s eyes watched his hips, both admiring and calculating. He dropped down onto his stool heavily and the plug shifted inside him. His breath caught slightly and he locked eyes with Grissom, telling him it was deliberate.

“And?” Grissom said, blinking, trying to focus his attention on the case.

“You’re not going to guess? Who do you think our bad guy is?” Greg asked. It was mostly just to keep Grissom there with him, keep him staring at Greg with that ‘I’m going to fuck you’ expression. 

“Greg, I don’t have time for this. Just tell me,” Grissom said, a command in his voice.

Greg sighed in disappointment. “Hector McGinnis, the boyfriend,” he responded, handing Grissom the evidence sheet. 

Grissom looked irritated. “We already know they had sex a few hours before Laura was killed.” He sighed, glancing away, his mind working this new information into his theory. “How is the blood evidence we found under her nails coming along?” 

“Still processing,” Greg said, pointing to the table full of evidence he still needed to work through.

Grissom eyed it disdainfully. “Right.” He glanced back at Greg, his eyes falling to his groin. He moved closer to the younger man, lowering his voice so their conversation would not be heard. “How are you doing?”

Greg moaned quietly, eyes still connected with Grissom’s. He smirked at the flash of surprise and arousal it created. “Perfect,” he purred.

Grissom’s mouth opened and he looked like he was going to say something Greg knew would make his dick throb, but then he changed his mind with a quick shake of his head. “Try to get to that blood evidence soon. I’ll come back to check on it in a little while.” 

Greg smiled as he watched Grissom leave, knowing he wasn’t just checking on the evidence. He turned the radio louder and focused on his work again. Still, he couldn’t help squirming more than he did on a regular night, his ass feeling full and naughty thoughts racing through his mind.

\-------------------------------------------------------------------------

Greg knocked on Grissom’s door just as the sun was starting to rise. He was given permission to enter. He found Grissom surrounded by paper at his desk, looking grumpy. He closed the door behind him. 

“I’m leaving now,” he said quietly, a pleasant calm washing over him. 

Grissom glanced at the clock and seemed surprised at the time. “Oh. Well, come here a minute.”

Greg did so happily, moving to the same side of the desk as Grissom and leaning against it. What he really wanted to do was crawl into Grissom’s lap and cuddle against him, but they couldn’t chance someone walking in.

“How are you feeling?” he asked meaningfully.

“Getting a little bit sore, but it’s not anything I can’t live with. I want to keep it in a little longer.”

“Greg, it’s been 15 hours. Don’t hurt yourself to prove a point.” Grissom gave him that look, the look which never failed to remind Greg of their age difference, simply because it was so paternal. 

“I’m not, I swear. I like how it feels.” He hesitated for a moment. “I like being sore.” A blush crept over his cheeks. 

Grissom’s eyebrow rose at that. He nodded slightly to himself, filing the information away for later. “I’ll be here a while longer. Do you have plans for when you get home?”

Greg nodded jerkily, unsure of what to think about the way Grissom didn’t mention his little confession. “I’m gonna shower, masturbate, then sleep a little while.” Grissom must be starting to influence him; if he had been talking to Nick or Warrick, he would have made some funny euphemism like spank the monkey or wax the   
whale. 

“Are you going to sleep with the plug?” Grissom asked. He found he liked the idea, liked thinking about Greg soft with sleep and dreams while the plug fucked into him with every movement he would make. 

Greg blinked. “I don’t know, didn’t think about it.” He stared at Grissom for a moment, saw the way Grissom’s dick was starting to tent his pants, and grinned. “Do you want me to?”

“I don’t want you to hurt yourself,” Grissom said, a little bit stern. His answer was clear though, if you spoke Grissom fluently, which Greg did. He wanted Greg to keep it in, but he was giving him a clear out.

“I’ll sleep with it then,” he replied, grinning wickedly. “Maybe when you’re finished work, you can come over and wake me up the way I like.” With Grissom’s fingers (or even better, his dick), already inside Greg, pressing him open, fucking him while Greg lay asleep. Sometimes he feels Grissom when they try this, waking up before he can really do anything, but he pretends to be asleep, tries to keep his breaths even and deep. He’s pretty sure Grissom knows he’s awake, but he never calls Greg out on it.

“Men’s bathroom, bring this,” Grissom said, pressing a small bottle of lube into Greg’s hand. Greg’s eyebrows shot up. They hardly ever fucked at work; Greg wanted to but Grissom thought it was too risky. But he wasn’t going to stop to question Grissom, so he simply nodded and tried to walk as casually as possible to the far men’s room. 

They had decided if they were ever going to fuck at work, it would have to be here. It was small, with only one toilet and sink, and very private. There were no offices in this area of the building, only records, so there was very little foot traffic. Knowing the chances of anyone interrupting or accidently overhearing them made it less thrilling for Greg, but it’s not like he would ever turn down sex with Grissom, anywhere.

He must have waited about 5 minutes before he saw the knob turn and Grissom step inside. But the wait was worth it as Grissom shoved his against the wall and captured his mouth with a rough kiss, tongue invading and demanding a response. Greg was already breathless by the time he pulled away.

Grissom grabbed his shoulder and turned his body around quickly. Greg’s hand moved up to the wall to support himself. He shoved his ass back, needy for Grissom’s dick. The hand grabbing at the front of his pants made him moan, even if Grissom was only trying to undo them so he could pull Greg’s trousers down over his ass. Greg wasn’t wearing underwear (he rarely did, too constraining) and Grissom bit his shoulder when he saw the bright red plug winking at him. Grissom played with it, shoving it in and out of Greg’s body at an agonizingly slow pace, loving how Greg’s breath changed into shorts gasps and hitches. 

“Keep fucking yourself with it,” Grissom ordered, shoving it inside Greg for the moment. He wanted to see the toy disappearing into Greg as he prepped himself to take its place. 

Greg grabbed the lube out of his pocket and handed it back to Grissom before doing as he was told, moving it faster than Grissom had. His forehead fell softly against the cold stone and he bit his lip to stop his moans. This place was isolated, but he knew he still had to be quiet.

He grinned with manic anticipation when Grissom knocked his hand away and pulled the plug out of him completely. Grissom grabbed his hips and slammed into him, biting his shoulder through his shirt as his balls rested against Greg’s ass. 

The thrusts were fast, hard, _dirty_ , and it would be over very soon for both of them. But this was really only a quickie and Grissom would fuck his young lover properly later. 

“Fuck,” Greg moaned as he fisted himself. His upper body was resting against the wall now and he didn’t try to push back on Grissom’s dick. He knew it would just fuck up this frantic rhythm they had established. He just leaned against the wall and took Grissom’s dick, took everything he had to offer, and then took Grissom’s cum when the older man finished inside him. He was panting, desperate for relief, wondering if his dick would be chafed from the speed with which he was jerking it. He came with a groan, his cum landing on the wall in front of him. 

With a sigh, he didn’t bother moving and realized Grissom hadn’t either. His dick was quickly softening within Greg’s body and Greg smiled lazily.   
Grissom nuzzled his neck and kissed him tenderly before pulling out. He placed a hand on Greg’s shoulder to keep him there. Inspecting the plug, he grinned wickedly. 

The experiment wasn’t over yet.


End file.
